The analytical Services Core will provide input in the design and analysis of all project, on this program project grant. It will also be responsible for the data collection, data base maintenance and analysis of clinical projects. The flow cytometry in this core will facilitate the analysis of cell kinetics and apoptosis that are required in this proposal. The facility will interact with individual investigators and provide input into experimental design, be responsible for all tumor disaggregation and staining procedures, run the samples, and analyze and interpret the data. The flow facility itself proposes to develop novel methods to measure the population dynamics of cells in tumors. In particular the investigators will define the influence that apoptotic cell death has on the estimates of cell kinetic parameters and extend their existing analytical procedures to incorporate the extra information that derives from knowledge of apoptotic rates. They propose that the kinetic parameters which previously have been measured (duration of S-phase, TS; the tumor potential doubling time, Tpot; S-phase fraction, SPF; labeling index, LI) be extend to include measurements of apoptotic frequency; growth factors, GF; and a quantify representing the mean lifetime of doomed cells, TL.